I have my fiction and non-fiction sorted into two different libraries. I'm using custom columns but both libraries have one called crime.historical.
If I have already (for instance) already transferred some of the fiction historical crime and want to transfer some of the non-fiction - would calibre make two crime/historical folders or just one?

I have my fiction and non-fiction sorted into two different libraries. I'm using custom columns but both libraries have one called crime.historical.
If I have already (for instance) already transferred some of the fiction historical crime and want to transfer some of the non-fiction - would calibre make two crime/historical folders or just one?

The Template has to be exactly the same.
Spelling,spacing and Case must be the same.

one tiny difference

Why not simply do a Test/Experiment? I can confirm that my PEz (V5) has not melted in all the times I have botched a template change )